African-Americans who smoke appear to be at greater risk for peripheral artery disease, or PAD, new research has found. Additionally, the findings suggest that smoking intensity – how many cigarettes a day and for how many years – also affects the likelihood of getting the disease.
PAD affects 8 to 12 million people in the United States and 202 million worldwide, especially those age 50 and older. It develops when arteries in the legs become clogged with plaque, fatty deposits that limit blood flow to the legs. Clogged arteries in the legs can cause symptoms such as claudication, pain due to too little blood flow, and increased risk for heart attack and stroke.
The impact of cigarette smoking on PAD has been understudied in African-Americans, even though PAD is nearly three times more prevalent in African-Americans than in whites. The current study looked at the relationship between smoking and PAD in participants in the Jackson Heart Study, the largest single site cohort study investigating cardiovascular disease in African-Americans.
The new research, as well as the Jackson Heart Study, are funded by the National Heart, Lung, and Blood Institute (NHLBI), and the National Institute of Minority Health and Health Disparities (NIMHD), both part of the National Institutes of Health. The new findings appear in the January issue of the Journal of the American Heart Association.
Even though PAD is more prevalent in African-Americans than in whites, prior studies about the disease did not include significant numbers of African-Americans. This limited the researchers’ ability to single out the specific effects of smoking in this population from other risk factors, such as hypertension, diabetes mellitus, and obesity.
For the study, researchers divided the 5,258 participants into smokers, past smokers and never smokers. After taking into account other risk factors, they assessed smoking intensity and found a dose-dependent link between cigarette smoking and PAD. Those smoking more than a pack a day had significantly higher risk than those smoking fewer than 19 cigarettes daily. Similarly, those with a longer history of smoking had an increased likelihood of the disease.
Clark noted important caveats. Despite strong associations between smoking and PAD, for example, the findings do not establish a causal link; nor can they be generalized to people of African descent from other regions or countries, since the Jackson Heart Study was conducted in a single community of African-Americans.
